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1.24.2012

Remember what the dormouse said...

Within a minute after subjects got an infusion of psilocybin, researchers said, scanners that plot blood flow within the brain detected a sudden drop in activity in the medial prefrontal cortex and the posterior cingulate cortex, two areas of the brain that appear to be key in "grounding" us in reality. These areas also are key nodes of the brain's newly identified Default Mode Network, which springs to life when our minds wander.

Thus untethered, the brain's sensory regions are free to soar. Subjects reported unusual changes in their visual experiences, including geometric patterns, distortions of space and size, and dreamlike perceptions. They reported that their thoughts and imaginations wandered, their perceptions of time were changed, and sounds they heard brought on vivid images -- a mingling of sights, sounds and thoughts such as those experienced by people with synaesthesia. And researchers noted that the more suppressed the observed activity in a subject's posterior cingulate cortex and medial prefrontal cortex, the more potent the sensory distortions the subject reported.